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Biomedical subjects

M Toyoda

Publications and source records attributed to M Toyoda.

At least 73 records · Page 4Linked to original sources
PubMed2001

[Application and improvement of aflatoxin analysis in foods using a multifunctional column and HPLC].

In an earlier report, we developed a rapid, sensitive and clean method consisting of non-chloroform extraction, clean-up on a commercial multifunctional cartridge column and HPLC with fluorescence detection for the analyses of aflatoxins. In this report, we applied this method to analyze aflatoxins in nuts, giant corn, cereals, spice and black teas. The method was effective for macadamia nuts, walnuts, hazelnuts, brazil nuts, giant corn, rice, wheat and buckwheat, and the recoveries of aflatoxins B1, B2, G1 and G2 spiked in them at the level of 10 ng/g were 85-106%. However, in the chromatograms of spices and black tea, many background peaks were observed. Therefore, we added a purification step with an affinity column to the clean-up of these samples with the multifunctional cartridge column. After the additional purification, most of the background peaks were gone. The recoveries of aflatoxins B1, B2 and G1 spiked at the level of 10 ng/g were 71-112% except for the case of B2 in white pepper (48%). The recoveries of G2 were 49-95%.

Aflatoxins↗
PubMed2001

[Two cases of episodic angioedema associated with eosinophilia].

We experienced two cases of limb edema of unknown pathogenesis. No evidence was found concerning involvement of the kidneys, heart of other visceral organs. Case 1 was 22-year-old woman. Her white blood cell count increased to 13,100/microliter with 65.0% eosinophils. Case 2 was a 27-year-old woman. Her white blood cell count increased to 23,300/microliter with 67.0% eosinophils. In these cases, extensive diagnostic evaluations revealed no evidence of atopy, neoplasms, collagen-vascular disease, or parasitic infestation. We diagnosed these cases as episodic angioedema with eosinophilia. In both cases, the angioedema improved gradually in parallel with a decrease in the white blood cell count. This disorder is very rare, but it is very important to consider it in differential diagnosis especially for nephrologists.

Adult↗
PubMed2001

[MR hydrography of the abdomen: technical consideration of data acquisition and future prospects for clinical applications].

Recent advances in MR hydrography have enabled various clinical applications in the areas of abdominal and pelvic disorders, for example, MR cholangiopancreatography (MRCP), MR urography(MRU), and MR hydrography of the fetus. Although the two-dimensional(2D) single-slice method provides excellent information as to the global relationship between lesions and various anatomical structures, small lesions or detailed anatomical characteristics may not be visualized owing to the partial volume effect. Source images of the 2D multislice method are most suitable for the detection of small lesions and detailed evaluation of anatomical structures as "tomographic imaging", while the three-dimensional(3D) method is useful in obtaining data sets for 3D imaging. MR hydrography is a promising method for the noninvasive evaluation of various abdominal disorders, and it has the potential to play new roles in various anatomical regions. However, knowledge of the proper indications is essential for successful clinical application.

Abdomen↗
PubMed2001

[A case of antiphospholipid antibody syndrome with variable renal histological change despite of poor changes in urinalysis].

We experienced a case of lupus nephritis with antiphospholipid antibody syndrome. A renal biopsy specimen from this patient showed various renal histological changes, but the results of urinalysis were almost normal. The patient was a 56-year-old woman diagnosed as having systemic lupus erythematosus with antiphospholipid antibody syndrome in 1983. In 1998, she had diarrhea and blood gas analysis showed metabolic acidosis. Therefore, she was admitted to our hospital and underwent renal function examination. The glomerular filtration rate was reduced(GFR: 40/ml/min), but urinalysis was almost normal. To examine her renal dysfunction, we performed open renal biopsy. Her renal tissues showed global glomerular sclerosis, mesangial cell proliferation and infiltration of cells in the tubulointerstitial area(WHO II). Furthermore, some arterioles showed organized thrombus formation and recanalization due to the antiphospholipid antibody syndrome. Renal biopsy of patients with lupus nephritis is useful not only for precise diagnosis, but also for the selection of appropriate treatment.

Antiphospholipid Syndrome↗
PubMed2001

Identification of missense mutation (G365R) of the butyrylcholinesterase (BCHE) gene in a Japanese patient with familial cholinesterasemia.

A point mutation which caused a silent phenotype of human serum butyrylcholinesterase (BChE) was identified in the genomic DNA of a 57-year-old Japanese woman who visited our hospital because of pneumonia. The propositus exhibited an unusually low level of BChE activity, whereas her son and daughter had an intermediate level. Immunologically, there was an absence of BChE protein in the propositus's serum. DNA sequence analysis of the propositus demonstrated a point mutation at codon 365 (GGA-CGA), resulting in a Gly-Arg substitution. A family study showed her son and daughter to have the same mutation.

Butyrylcholinesterase↗
PubMed2000

Induction of active systemic anaphylaxis by oral sensitization with ovalbumin in mast-cell-deficient mice.

Mast-cell-deficient W/W(v) mice were sensitized by oral administration of 0.1 and 1.0 mg ovalbumin (OVA) by gavage every day for 9 weeks, and active systemic anaphylaxis (ASA) was induced by intraperitoneal injection of OVA. The production of OVA-specific IgE and IgG1 by oral immunization of the W/W(v) mice was high, and the production of IL-4 by splenocytes re-stimulated with OVA in vitro was increased. In contrast, production of OVA-specific IgG2a and IgG2b was low, and production of IFN-gamma by splenocytes after re-stimulation with OVA in vitro was rather decreased. These findings suggest that Th2-dominant helper T-cell activation had occurred. No increase in serum histamine level was observed following ASA induction. However, the plasma platelet-activating factor (PAF) levels of the mice sensitized with 0.1 and 1.0 mg OVA by gavage increased significantly. The increases in plasma PAF correlated well with the ASA-associated decreases in body temperature, suggesting that PAF plays an important role in ASA in W/W(v) mice. Taken together the above findings indicate that W/W(v) mice are a good model not only for studying induction of food allergy but also for examining the role of PAF in food-induced hypersensitivity.

Administration, Oral↗
PubMed2000

Hydrophobic extracts of a Chinese herb (CMX-13) exhibit potent immunosuppressive properties and prevent acute rejection in a highly histoincompatible model of rat lung transplantation.

BACKGROUND: The potential of higher plants as sources for new immunosuppressive medications is well recognized. In our experiments we investigated the immunosuppressive effect of a highly refined and potent extract of a Chinese herbal preparation, CMX-13, on inhibiting acute allograft rejection (AR) in a highly histoincompatible rat lung transplant model, BN-->LEW, and on lymphocyte activation and cytokine gene expression in vitro. METHODS: Left lung transplants: the control group (group 1) received only dimethylsulfoxide (DMSO) which is the solvent for CMX-13. Group 2 received intramuscular cyclosporin A (CsA, 25 mg/kg) on day 2 posttransplant. Group 3 and 4 received i.p. CMX-13 (0.5 mg/day, low dose and 5 mg/day, high dose, respectively) on day 1, 2, and 3 posttransplant. All animals were killed on day 6 posttransplant. Several pathological categories of inflammation were examined. In vitro experiments: rat spleen cells were incubated with Con A or irradiated stimulator cells with/without serial dilutions of CMX-13 or CsA. Cell proliferation was measured by 3H-thymidine incorporation. mRNA expression of interleukin-2 and interferon-gamma was examined by reverse transcriptase-polymerase chain reaction. RESULTS: The severity of AR in animals receiving high dose CMX-13 was significantly reduced (stage II, P<0.05) compared with controls (stage IV). Significant differences were also seen when more specific parameters of inflammation were examined (necrosis, 0 vs. 1.7+/-1.0, P<0.05; interalveolar hemorrhage, 0 vs. 3.0+/-0.9, P<0.05). The responses seen in the animals treated with high dose CMX-13 were similar to those in the CsA group. CMX-13 inhibited T cell proliferative responses induced by Con A and alloantigen stimulation in a dose-dependent manner that were similar to CsA. Interleukin-2, and interferon-gamma mRNA expression in Con A-stimulated spleen cells was not inhibited by CMX-13 although CsA showed significant inhibition. CONCLUSIONS: 1) CMX-13 significantly reduces the stage of AR and parameters of inflammation in a highly histoincompatible rat lung transplant model. 2) CMX-13 has equal potency to CsA in the inhibition of Con A and alloantigen stimulated rat spleen cell proliferation. 3) CMX-13 showed no inhibitory effects on IL-2 and gamma-IFN mRNA expression, suggesting that its mechanism of action is different from CsA. 4) CMX-13 or derivatives may have potential utility as an immunosuppressive agent(s) in modulation of AR and management of other inflammatory and immunological disorders.

Acute Disease↗
PubMed2000

Jumonji is a nuclear protein that participates in the negative regulation of cell growth.

The jumonji (jmj) gene, obtained by a gene trap strategy, is essential for mouse embryogenesis and is suggested to play important roles in cell growth during development. The amino acid sequence of the Jmj protein includes a nuclear localization signal and a DNA binding motif called the AT-rich interaction domain (ARID). To investigate the biological functions of the Jmj protein, we prepared specific antibodies. Using these antibodies, we showed that the Jmj protein is a 160-kDa protein and localizes in the nuclei of COS-7 cells transfected with jmj cDNA and megakaryocytes from fetal liver which show strong endogenous expression of the jmj gene. Moreover, overexpression of the Jmj protein in COS-7 and NIH3T3 cells remarkably reduced cell proliferation compared with control cells transfected with vector alone. These results show that the Jmj protein acts in cell nuclei and participates in the negative regulation of cell proliferation signaling.

3T3 Cells↗
PubMed2000

Construction of a new multi-turn time-of-flight mass spectrometer.

A new type of multi-turn time-of-flight mass spectrometer was constructed, consisting of four cylindrical electric sectors and 28 electric quadrupole lenses, the size of the vacuum chamber being 60 x 70 x 20 cm. It was demonstrated that the mass resolution can be increased according to the number of cycles of the ions through the ion optical system.

Mass Spectrometry↗
PubMed2000

An ultrastructural study of pigmented purpuric dermatitis with special reference to fibrous long-spacing collagen.

A case of pigmented purpuric dermatitis (PPD) in a Japanese man aged 59 years is reported with an interesting ultrastructural finding. Clinically, the lesions, which consisted of telangiectatic puncta and pigmentation, were irregular in shape and occurred predominantly on the lower legs without pruritus. Histologically, lymphocytic perivascular infiltrates and extravasation of red blood cells were observed in the papillary dermis. Ultrastructurally, endothelial cells with ovoid nuclei showed swelling and the lumen of the capillary became narrowed. Several banded structures, so-called fibrous long-spacing collagen (FLSC), were observed in the cytoplasm. They were spindle shaped, about 5 microm in length, and showed crossbands of 300-nm-wide intervals with fine intraperiodic bands. These structures were not observed in dermal connective tissue and fibroblasts. These results suggested that FLSC was synthesized in endothelial cells rather than being phagocytosed by endothelial cells, which might be helpful in investigating the etiology of PPD.

Collagen↗
PubMed2000

Development of mushrooms for thrombosis prevention by protoplast fusion.

With thrombosis a major cause of death in Japan and the Western world, thrombin-inhibitory agents that constrain the formation of fibrin are sought. We screened for basidiomycetes showing anti-thrombin activity and isolated Laetiporus sulphureus. However, it was difficult to cultivate and its form was not satisfactory. We therefore used protoplast fusion between L. sulphureus and the commonly cultivated basidiomycete Hypsizygus marmoreaus to obtain cultivable basidiomycetes that produced an anti-thrombin substance. For the protoplast fusion of L. sulphureus and H. marmoreaus, the protoplast concentration, alternating electric field intensity, dielectrophoresis duration, and field pulse intensity used were of 1 x 10(7) protoplasts/ml, 100 V/cm.1 MHz, 60 s, and 8 kV/cm, respectively. The number of regenerated colonies obtained was 4961, from which 43 strains were selected for electrophoretic analysis. Four of the fusants were found to have a band from each parent in isozyme patterns obtained using their crude extract. The fruiting bodies of the fusants were very similar to those of H. marmoreaus. Crude extract from each of the fusants and from L. sulphureus showed anti-coagulative activity in terms of the thrombin clotting time. We thus obtained improved basidiomycetes that produce an anti-thrombin substance, are easily cultivated, and whose form resembles H. marmoreaus, a commonly used culinary mushroom.

Journal Article↗
PubMed2000

CD30 expression on circulating memory CD4+ T cells as a Th2-dominated situation in patients with atopic dermatitis.

Th2 clones have been reported to express CD30 preferentially, but whether T cells producing Th2-type cytokines may favor CD30 expression in the in vivo state remains unknown. We investigated the expression of CD30 on circulating T cells in atopic dermatitis (AD) as a Th2-dominated disorder. Peripheral blood mononuclear cells were prepared from 51 AD patients and 14 nonatopic controls, and their phenotypes were analyzed with flow cytometry. Cytokine production by stimulated CD4+ T cells was also assessed by the single-cell-staining method. Flow cytometric analysis clearly revealed that CD30+ T cells were identifiable in the blood of AD patients with greater frequency compared to controls. The important finding was that CD30 expression was restricted to a small but substantial population of memory (CD45RO+) CD4+ T cells, but not CD8+ ones. In AD patients, it was demonstrated that the percentages of CD30+ cells within CD45RO+ CD4+ T cells correlated well with the disease severity, serum IgE levels, peripheral eosinophil counts, and tendency toward Th2-dominant cytokine pattern as determined by the ratio of interleukin-4 to interferon-gamma production. This study suggests that CD30 expression in circulating T cells might serve as an in vivo marker for the Th2-dominated condition.

Adolescent↗
PubMed2000

Immunohistochemical localization of ornithine decarboxylase in skin tumors.

BACKGROUND: Ornithine decarboxylase (ODC) plays an important role in the biosynthesis of polyamines. Induction of ODC and polyamine synthesis has been demonstrated in neoplastic tumors and is thought to be related to the degree of malignancy. METHODS: In this study, we investigated a series of basal cell epitheliomas (BCE), Bowen's disease, squamous cell carcinomas (SCC), and metastatic tumors of the skin using an antibody against ODC for immunohistochemistry. RESULTS: Eight of 12 cases of BCE failed to show a positive reaction for ODC. In Bowen's disease, 5 of 13 cases diffusely showed positive reaction for ODC. Fourteen of 15 cases of SCC showed ODC expression, the intensity of which was decreased in the peripheral layer. At higher magnification, the distribution of ODC in the positive SCC cases showed granular and heterogenous patterns. Ten of 14 cases of metastatic skin tumors exhibited positive reactions, and well-differentiated adenocarcinomas tended to show more strongly positive than poorly-differentiated ones. CONCLUSIONS: These results support the conclusion that the intensity and the incidence of positive immunohistochemical staining for ODC correlate with the degree of cellular differentiation, and furthermore, that heterogenous distribution of ODC staining may be associated with heterogeneity of tumor cells.

Bowen's Disease↗
PubMed2000

Iron enhances hepatitis C virus replication in cultured human hepatocytes.

BACKGROUND: Iron overload in the presence of increasing concentrations of iron is one of the indicators of poor response to interferon therapy in chronic hepatitis C. In order to analyze the effect of iron on hepatitis C virus (HCV) replication, we measured replication in an HCV-infected cell line. METHODS AND RESULTS: Cells from a non-neoplastic HCV-infected human hepatocyte line (PH5CH8) susceptible to HCV infection and supportive of HCV replication were used in this study. The replication of HCV RNA was measured by reverse transcription-nested polymerase chain reaction (RT-nested PCR). PH5CH8 cell viability was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. PH5CH8 cells were incubated with 0, 1, 10, 50, and 100 microM of FeSO4 at 37 degrees C with 5% CO2. Forty-eight hours after iron supplementation, the quantity of HCV RNA in the cells incubated in 50 and 100 microM of FeSO4 was approximately ten times that of the cells with no iron supplementation. Similar changes were observed beginning at 12 h from supplementation with FeSO4 and continued for at least 72 h after supplementation. MTT assay indicated that iron did not have cytotoxic effects on the PH5CH8 cells. CONCLUSION: Iron enhances HCV replication in a hepatocyte cell line. The results suggest that iron deposition in hepatocytes could facilitate HCV infection in the liver.

Cell Line, Transformed↗
PubMed2000

Role of serum soluble Fas/soluble Fas ligand and TNF-alpha on response to interferon-alpha therapy in chronic hepatitis C.

AIMS/BACKGROUND: To determine the relationship between host factors and host response to interferon (IFN) therapy, serum soluble Fas (sFas), soluble Fas ligand (sFas ligand), and tumor necrosis factor-alpha (TNF-alpha) were analyzed in 41 patients with chronic hepatitis C (CH-C) treated with IFN-alpha. METHODS: Serum levels of sFas, sFas ligand, and TNF-alpha were measured at 0, 4, and 24 weeks of IFN therapy. RESULTS: Eighteen patients were complete responders (CR) and 23 patients were non-responders (NR). Serum levels of sFas and TNF-alpha in patients with CHC were significantly higher than those in healthy controls (p<0.01 and p<0.01, respectively). Serum sFas ligand levels were significantly lower in CH-C patients than in healthy controls (p<0.01). Before IFN therapy, serum levels of sFas in NR were significantly higher than those in CR (p<0.05). At 4 weeks of IFN therapy, serum levels of sFas of CR were significantly elevated compared with levels before IFN therapy (p<0.05). Serum levels of sFas correlated with the histological activity of the liver (p<0.05) and alanine aminotransferase (p<0.05). None of the three parameters, serum sFas, sFas ligand, or TNF-alpha levels, correlated with each other, with HCV-RNA genotype or with serum HCV-RNA load. Multiple logistic regression analysis showed that serum sFas levels before IFN therapy were a contributive factor to predict efficacy of IFN therapy. CONCLUSIONS: Serum sFas/sFas ligand and TNF-alpha play a possible role in pathogenesis of CH-C and also in IFN therapy. Serum sFas levels before IFN therapy may be one of the host-related factors used for evaluating the response of CH-C patients to IFN therapy.

Adult↗